Unless you can show something critical about the placement of deuterium (instead of just scattering deuterium anywhere you can), it’s probably obvious. I once used this reference to show that even if you only substitute deuterium for hydrogen at very specific carbon atoms on thalidomide, those particular carbon atoms were known to be troublemakers. There are going to be more pharmacokinetic studies of known therapeutic compounds where people will demonstrate that certain portions of molecules were known metabolic liabilities. So it’s obvious to start there when you add deuterium.